Rigid

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The cold or winter rigor is a state in which cold- blooded (poikilothermal) animals fall when the temperature falls below the tolerated minimum.

physiology

The hibernation is in contrast to hibernate in the same warm initiated mandatory animals from falling temperatures, it is not chronobiologically regulated. The body temperature corresponds to the outside temperature, all life processes are reduced with falling temperatures according to the RGT rule , so that the animal does not actively end the rigid winter months, but freezes to death if the temperatures are too low. The heartbeat per minute is usually very low, as is the breathing rate. The cardiac output drops significantly. The eyes are also left open when the cold is frozen. Movements are not possible during the freezing cold, nor can food be consumed.

Frogs can absorb oxygen through their skin underwater. Turtles take in oxygen in the water through the mouth and throat, some also through two thin-walled bags in the cloaca ( anal bladder ), each of which is equipped with tiny surface structures (papillae) with blood vessels running through it. In addition, turtles that hibernate on the bottom of water are able to generate energy under anaerobic conditions ( anaerobic glycolysis ).

Animal species

Many insects , snails , amphibians (e.g. frogs and toads ) and reptiles (e.g. lizards , snakes , turtles ) are among the animals that survive the winter in freezing cold in the colder climates .

Pond newts spend three to four months, blindworms and adders four to five months, tree frogs and sand lizards five to six months in a state of winter rigor. An increased concentration of glucose in the body fluids can prevent fatal freezing in light frost .

See also

Web links

Individual evidence

  1. ^ Jeanette Wyneken, Matthew H. Godfrey, Vincent H. Bells. (Eds.): Biology of turtles. Taylor & Francis Group. 2008. p. 307
  2. ↑ Like a fish in water: Turtle species lives six months without surfacing ( Memento from December 8, 2015 in the Internet Archive )